It is known for the appearance and weather resistance of screws to be improved by mounting caps onto the heads of the screws so as to form screw/cap assemblies.
More particularly, modern buildings often have cladding or roofing of a color different from the color of the screws used to fasten the cladding or roofing to the underlying foundation. The heads of the screws can be visually obtrusive, appearing from a distance as rows of dots against an otherwise uniformly colored background. When exposed to the weather, the heads of the screws can become attacked by means of the atmosphere and thereby develop rust, and this can lead to weakening of the structural integrity of the screw as well as further detracting from the desired overall visual impression of the building structure.
In an attempt to overcome these disadvantages, colored caps have been applied by hand to the heads of the screws after the screws have been threadly inserted. The caps can be formed of a plastic material and the screws can be formed of a metallic material. The colored caps can then blend with the colored background so as to disguise the presence of the screws and to protect the screws from the weather. Unfortunately, not only is the application of the caps to the heads of the screws a time-consuming operation, but the caps tend to fall off the heads of the screws.
The conventional answer to these additional problems has been to mold the caps around specially shaped heads of the screws in for example an insert-molding machine. Although technically successful it requires the manufacturer to maintain large stocks if long delivery times are to be avoided. Maintenance of large stocks is expensive because there is a need for more than forty different colors or types of caps and approximately ten different types or lengths of screws.